The invention provides a break monitoring device for a protection circuit of a switch cabinet. The break monitoring device comprises a power supply, an electronic switch, an AD (analog/digital) conversion module, an MCU (microprogrammed control unit) and an MMI. The power supply is connected with the electronic switch; the electronic switch is connected with the protection circuit of a pressing plate of the switch cabinet; the AD conversion module is used for acquiring a signal of the protection circuit of the pressing plate of the switch cabinet, and the signal is provided for the MCU for operation processing after being converted into a digital signal; the MCU is used for controlling the MMI to display output alarm information. The break monitoring device provided by the invention has the advantages that the structure is simple, the use is convenient, the manufacturing cost is low, the performance is reliable, the reliability of mains supply is improved, and the maintenance is convenient.